A023285 Primes that remain prime through 3 iterations of function f(x) = 5x + 6.

7, 79, 181, 233, 359, 401, 449, 1009, 1093, 1259, 1303, 1373, 1511, 1931, 2011, 2339, 2477, 3019, 3691, 4349, 4409, 5417, 5879, 6301, 6553, 6637, 7079, 8329, 9127, 9137, 10303, 10499, 11579, 12391, 13259, 14251, 15101, 15107, 15217, 15329, 15527, 15679

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Primes p such that 5*p+6, 25*p+36 and 125*p+186 are also primes. - Vincenzo Librandi, Aug 04 2010

Links

• John Cerkan, Table of n, a(n) for n = 1..10000

Crossrefs

Subsequence of A023219, A023254, and of A081759.

Programs

Magma

[n: n in [1..150000] | IsPrime(n) and IsPrime(5*n+6) and IsPrime(25*n+36) and IsPrime(125*n+186)] // Vincenzo Librandi, Aug 04 2010

Mathematica

p3Q[n_]:=And@@PrimeQ/@NestList[5#+6&,n ,3]; Select[Prime[Range[2000]],p3Q] (* Harvey P. Dale, Feb 20 2011 *)